From 44fa21d6489ec8e9ebd5731f479ed316940501fb Mon Sep 17 00:00:00 2001
From: Vladimir Yushutin <vyushut@clemson.edu>
Date: Mon, 13 Mar 2023 13:51:28 -0400
Subject: [PATCH] both 2D and 3D cases with sparsity pattern printed out; the
 test description is added; headers are trimmed;

---
 .../flux_sparsity_pattern_visiting_once.cc    | 130 ++++++++----------
 ...flux_sparsity_pattern_visiting_once.output |  23 +++-
 2 files changed, 75 insertions(+), 78 deletions(-)

diff --git a/tests/sparsity/flux_sparsity_pattern_visiting_once.cc b/tests/sparsity/flux_sparsity_pattern_visiting_once.cc
index 31ebb6b460..649019513a 100644
--- a/tests/sparsity/flux_sparsity_pattern_visiting_once.cc
+++ b/tests/sparsity/flux_sparsity_pattern_visiting_once.cc
@@ -14,112 +14,92 @@
  * ---------------------------------------------------------------------
  */
 
-// @sect3{Include files}
-
-#include <deal.II/base/convergence_table.h>
-#include <deal.II/base/tensor.h>
+// @sect3{This test considers two elements which share a common, regular face.
+// The logic of make_flux_sparsity_pattern() loops over all faces and filters
+// some of them according to a predicate face_has_flux_coupling(). We check
+// that the only internal face in the current setup is visited exactly once and
+// that the predicate face_has_flux_coupling() is evaluated once for this face.}
 
 #include <deal.II/dofs/dof_tools.h>
 
 #include <deal.II/fe/fe_q.h>
-#include <deal.II/fe/fe_values.h>
-#include <deal.II/fe/mapping_q1.h>
 
-#include <deal.II/grid/filtered_iterator.h>
 #include <deal.II/grid/grid_generator.h>
-#include <deal.II/grid/grid_out.h>
-#include <deal.II/grid/tria.h>
 
-#include <deal.II/lac/affine_constraints.h>
 #include <deal.II/lac/dynamic_sparsity_pattern.h>
-#include <deal.II/lac/solver_control.h>
-#include <deal.II/lac/sparse_direct.h>
-#include <deal.II/lac/sparsity_pattern.h>
-
-#include <deal.II/numerics/data_out.h>
-#include <deal.II/numerics/vector_tools.h>
-
-#include <fstream>
 
 #include "../tests.h"
 
+using namespace dealii;
 
+template <int dim>
+Triangulation<dim>
+make_two_elements()
+{
+  Triangulation<dim> triangulation;
+  GridGenerator::hyper_cube(triangulation, -2.0, 2.0);
+  triangulation.begin_active()->set_refine_flag(
+    RefinementCase<dim>::cut_axis(0));
+  triangulation.execute_coarsening_and_refinement();
+  return triangulation;
+}
 
-// @sect3{The main() function}
-// test that a face is visited once
-using namespace dealii;
 
 template <int dim>
 bool
-is_face_on_OY(const typename Triangulation<dim>::active_cell_iterator &cell,
-              const unsigned int face_index)
+is_face_on_OY(const typename DoFHandler<dim>::active_cell_iterator &cell,
+              const unsigned int                                    face_index)
 {
-  bool on_OY = (std::abs(cell->face(face_index)->center()(0)) < 0.01);
-  deallog.get_file_stream()
-    << "This sentence should appear once when the corresponding face is visited only once"
-    << std::endl;
-  deallog.get_file_stream() << cell->index() << std::endl;
-  return on_OY;
+  deallog
+    << "This sentence should appear once when the corresponding face is visited only once on cell "
+    << cell->index() << std::endl;
+  return (std::abs(cell->face(face_index)->center()(0)) < 0.01);
 }
 
 template <int dim>
 void
-make_two_elements(Triangulation<dim> &triangulation)
+create_and_output_flux_sparsity_with_filter(
+  DoFHandler<dim> &                       dof_handler,
+  std::function<bool(const typename DoFHandler<dim>::active_cell_iterator,
+                     const unsigned int)> filter)
 {
-  GridGenerator::hyper_cube(triangulation, -2.0, 2.0);
-  triangulation.begin_active()->set_refine_flag(
-    RefinementCase<dim>::cut_axis(0));
-  triangulation.execute_coarsening_and_refinement();
+  DynamicSparsityPattern dsp(dof_handler.n_dofs(), dof_handler.n_dofs());
+  DoFTools::make_flux_sparsity_pattern(
+    dof_handler,
+    dsp,
+    AffineConstraints<double>(),
+    true,
+    Table<2, DoFTools::Coupling>(1, 1, new auto(DoFTools::always)),
+    Table<2, DoFTools::Coupling>(1, 1, new auto(DoFTools::always)),
+    numbers::invalid_subdomain_id,
+    [&](const auto &cell, const unsigned int face_index) {
+      return filter(cell, face_index);
+    });
+  dsp.print(deallog.get_file_stream());
 }
 
 template <int dim>
 void
-create_flux_pattern_with_filter(DoFHandler<dim> &       dof_handler,
-                                DynamicSparsityPattern &dsp)
+check()
 {
-  Table<2, DoFTools::Coupling> cell_coupling(1, 1);
-  Table<2, DoFTools::Coupling> face_coupling(1, 1);
-  cell_coupling[0][0] = DoFTools::always;
-  face_coupling[0][0] = DoFTools::always;
-
-  const AffineConstraints<double> constraints;
-  const bool                      keep_constrained_dofs = true;
-
-  const auto face_has_flux_coupling = [&](const auto &       cell,
-                                          const unsigned int face_index) {
-    return is_face_on_OY<dim>(cell, face_index);
-  };
-
-  DoFTools::make_flux_sparsity_pattern(dof_handler,
-                                       dsp,
-                                       constraints,
-                                       keep_constrained_dofs,
-                                       cell_coupling,
-                                       face_coupling,
-                                       numbers::invalid_subdomain_id,
-                                       face_has_flux_coupling);
+  // create a square with two elements
+  const Triangulation<dim> tria = make_two_elements<dim>();
+  // Generate Q1 dofs for the mesh grid
+  DoFHandler<dim> dof_handler(tria);
+  dof_handler.distribute_dofs(FE_Q<dim>(1));
+  // create and output the sparsity pattern by using a filter
+  create_and_output_flux_sparsity_with_filter<dim>(dof_handler,
+                                                   is_face_on_OY<dim>);
 }
 
-
 int
 main()
 {
   initlog();
-  const int dim = 2;
-
-  // create a square with two elements
-  Triangulation<dim> triangulation;
-  make_two_elements(triangulation);
-
-  deallog << "dealii::Sparsity" << std::endl;
-  {
-    // Generate Q1 dofs for the mesh grid
-    DoFHandler<dim> dof_handler(triangulation);
-    const FE_Q<dim> finite_element(1);
-    dof_handler.distribute_dofs(finite_element);
-
-    // Compute the sparsity pattern specifying a face filter
-    DynamicSparsityPattern dsp(dof_handler.n_dofs(), dof_handler.n_dofs());
-    create_flux_pattern_with_filter(dof_handler, dsp);
-  }
+  deallog.push("2d");
+  check<2>();
+  deallog.pop();
+  deallog.push("3d");
+  check<3>();
+  deallog.pop();
 }
diff --git a/tests/sparsity/flux_sparsity_pattern_visiting_once.output b/tests/sparsity/flux_sparsity_pattern_visiting_once.output
index 22c63b1009..f8d6d502e1 100644
--- a/tests/sparsity/flux_sparsity_pattern_visiting_once.output
+++ b/tests/sparsity/flux_sparsity_pattern_visiting_once.output
@@ -1,4 +1,21 @@
 
-DEAL::dealii::Sparsity
-This sentence should appear once when the corresponding face is visited only once
-1
+DEAL:2d::This sentence should appear once when the corresponding face is visited only once on cell 1
+[0,0,1,2,3,4,5]
+[1,0,1,2,3,4,5]
+[2,0,1,2,3,4,5]
+[3,0,1,2,3,4,5]
+[4,0,1,2,3,4,5]
+[5,0,1,2,3,4,5]
+DEAL:3d::This sentence should appear once when the corresponding face is visited only once on cell 1
+[0,0,1,2,3,4,5,6,7,8,9,10,11]
+[1,0,1,2,3,4,5,6,7,8,9,10,11]
+[2,0,1,2,3,4,5,6,7,8,9,10,11]
+[3,0,1,2,3,4,5,6,7,8,9,10,11]
+[4,0,1,2,3,4,5,6,7,8,9,10,11]
+[5,0,1,2,3,4,5,6,7,8,9,10,11]
+[6,0,1,2,3,4,5,6,7,8,9,10,11]
+[7,0,1,2,3,4,5,6,7,8,9,10,11]
+[8,0,1,2,3,4,5,6,7,8,9,10,11]
+[9,0,1,2,3,4,5,6,7,8,9,10,11]
+[10,0,1,2,3,4,5,6,7,8,9,10,11]
+[11,0,1,2,3,4,5,6,7,8,9,10,11]
\ No newline at end of file
-- 
2.39.5